Measuring arrangement and method of directing and detecting particles

Abstract

A measuring arrangement includes an electrostatic concentrator, a surface and an imaging sensor which are configured to detect particles.

The invention claimed is: 
     
       1. A measuring arrangement
 comprising: 
 an electrostatic concentrator configured to direct particles to be verified toward a surface; 
 an imaging sensor configured to detect the particles directed onto the surface; 
 the electrostatic concentrator comprising a field electrode which is arranged in the surface or on the surface or adjacently to the surface and is configured to generate an inhomogeneous electrostatic field so as to direct the particles to be verified toward the surface; and 
 wherein a field electrode of the electrostatic concentrator is configured to comprise at least one electrode strip, a width of the at least one electrode strip being smaller than the largest extension of a photosensitive individual cell of the imaging sensor. 
 
     
     
       2. The measuring arrangement as claimed in  claim 1 , the measuring arrangement being configured such that temporary adhesion of the particles to the surface enables sensing of the adhered particles on the part of the imaging sensor. 
     
     
       3. The measuring arrangement as claimed in  claim 1 , wherein a layer, toward the surface of which the particles are directed, is part of the imaging sensor or is arranged adjacently to said imaging sensor, and
 wherein the field electrode configured to generate an electrostatic field for deflecting the particles to be verified is arranged, in the direction of incident light, in front of the imaging sensor or on a surface of the imaging sensor. 
 
     
     
       4. The measuring arrangement as claimed in  claim 1 , wherein a field electrode of the electrostatic concentrator comprises a transparent electrode material. 
     
     
       5. The measuring arrangement as claimed in  claim 1 , wherein a counter electrode is arranged at a distance from the field electrode, so that an inhomogeneous electric field directing particles toward the surface may be generated within a flow channel extending between the counter electrode and the surface. 
     
     
       6. The measuring arrangement as claimed in  claim 1 , wherein the surface is arranged, in a direction of incident light, adjacently to an imaging sensor, and
 the measuring arrangement being configured to detect cast shadows or a shadow image of particles directed toward the surface or adhering to the surface. 
 
     
     
       7. The measuring arrangement as claimed in  claim 1 , wherein the surface is arranged at a distance from an imaging sensor, an optical system comprising lens optics or mirror optics being arranged between the surface and the imaging sensor so as to image the particles directed toward the surface or the surface provided with adhered particles onto the imaging sensor. 
     
     
       8. The measuring arrangement as claimed in  claim 1 , the measuring arrangement being configured to generate a field strength of at least 30 kV/m in the surroundings of a field electrode of the electrostatic concentrator. 
     
     
       9. The measuring arrangement as claimed in  claim 1 , the measuring arrangement comprising several detection areas, a second one of the detection areas being configured to detect particles which have covered a larger distance through an electrostatic field generated by the electrostatic concentrator than particles detected by the first one of the detection areas. 
     
     
       10. The measuring arrangement as claimed in  claim 1 , the measuring arrangement being configured to temporarily switch off the field of the electrostatic concentrator so as to enable detachment of particles from the surface. 
     
     
       11. The measuring arrangement as claimed in  claim 1 , the measuring arrangement being configured to apply image recognition to the signal of the imaging sensor for qualitative determination of particles. 
     
     
       12. The measuring arrangement as claimed in  claim 11 , the measuring arrangement being configured to classify particles on the basis of the signal of the imaging sensor by means of a database. 
     
     
       13. The measuring arrangement as claimed in  claim 11 , the measuring arrangement being configured to classify particles on the basis of the signal of the imaging sensor by means of their shapes. 
     
     
       14. The measuring arrangement as claimed in  claim 11 , the measuring arrangement being configured to classify particles on the basis of the signal of the imaging sensor by means of their diffraction patterns or scattering patterns. 
     
     
       15. The measuring arrangement as claimed in  claim 11 , the measuring arrangement being configured to take into account, when classifying the particles, a wavelength dependence of image information sensed by the imaging sensor. 
     
     
       16. The measuring arrangement as claimed in  claim 1 , wherein an air flow meter is arranged to sense the velocity of the gas flow passing the surface of the electrostatic concentrator. 
     
     
       17. The measuring arrangement as claimed in  claim 16 , wherein the air flow meter is arranged on a surface along with a field electrode of the electrostatic concentrator. 
     
     
       18. The measuring arrangement as claimed in  claim 1 ,
 the measuring arrangement comprising a filter, 
 wherein the filter is arranged at a fluidic input of the measuring arrangement and is configured to filter out any particles whose sizes exceed a predefined size threshold. 
 
     
     
       19. The measuring arrangement as claimed in  claim 1 ,
 the measuring arrangement comprising a control element, 
 wherein the control element is arranged at a fluidic input or at a fluidic output of the measuring arrangement and is configured to influence a flow volume of a fluid flowing through the measuring arrangement. 
 
     
     
       20. The measuring arrangement as claimed in  claim 19 , the measuring arrangement being configured to control the control element on the basis of flow volume information provided by a flow volume meter so as to regulate a flow of fluid passing the surface of the electrostatic concentrator. 
     
     
       21. A measuring arrangement
 comprising: 
 an electrostatic concentrator configured to direct particles to be verified toward a surface; 
 an imaging sensor configured to detect the particles directed onto the surface; 
 the electrostatic concentrator comprising a field electrode which is arranged in the surface or on the surface or adjacently to the surface and is configured to generate an inhomogeneous electrostatic field so as to direct the particles to be verified toward the surface; 
 wherein the surface toward which the particles are directed is separated from the imaging sensor by one or more transparent layers; and 
 the measuring arrangement comprising a shielding electrode configured to at least partly shield an electric field of the electrostatic concentrator off from the imaging electronics of the imaging sensor. 
 
     
     
       22. A measuring arrangement
 comprising: 
 an electrostatic concentrator configured to direct particles to be verified toward a surface; 
 an imaging sensor configured to detect the particles directed onto the surface; 
 the electrostatic concentrator comprising a field electrode which is arranged in the surface or on the surface or adjacently to the surface and is configured to generate an inhomogeneous electrostatic field so as to direct the particles to be verified toward the surface: 
 the measuring arrangement comprising several detection areas, a second one of the detection areas being configured to detect particles which have covered a larger distance through an electrostatic field generated by the electrostatic concentrator than particles detected by the first one of the detection areas; 
 wherein the first detection area has a first electrode of the electrostatic concentrator associated with it which is configured to direct particles toward the first detection area, 
 wherein the second detection area has a second electrode of the electrostatic concentrator associated with it which is configured to direct particles toward the second detection area, 
 wherein an extension of the second electrode in a main direction of flow of the particles is larger than an extension of the first electrode in the main direction of flow of the particles. 
 
     
     
       23. A measuring arrangement
 comprising: 
 an electrostatic concentrator configured to direct particles to be verified toward a surface; 
 an imaging sensor configured to detect the particles directed onto the surface; 
 the electrostatic concentrator comprising a field electrode which is arranged in the surface or on the surface or adjacently to the surface and is configured to generate an inhomogeneous electrostatic field so as to direct the particles to be verified toward the surface; and 
 the measuring arrangement comprising a micromechanical element configured to enable detachment of particles adhering to the surface. 
 
     
     
       24. A measuring arrangement
 comprising: 
 an electrostatic concentrator configured to direct particles to be verified toward a surface; 
 an imaging sensor configured to detect the particles directed onto the surface; 
 the electrostatic concentrator comprising a field electrode which is arranged in the surface or on the surface or adjacently to the surface and is configured to generate an inhomogeneous electrostatic field so as to direct the particles to be verified toward the surface; and 
 the measuring arrangement being configured to temporarily generate an inhomogeneous electrostatic field whose field strength increases starting from the surface and which is configured to move particles away from the surface. 
 
     
     
       25. A method of detecting particles, comprising;
 directing particles to be verified toward a surface on the part of an electrostatic concentrator; 
 detecting the particles directed onto the surface on the part of an imaging sensor; 
 the electrostatic concentrator comprising a field electrode which is arranged in the surface or on the surface or adjacently to the surface, and generates an inhomogeneous electrostatic field so as to direct the particles to be verified toward the surface; and 
 the method comprises temporarily generating an inhomogeneous electrostatic field whose field strength increases starting from the surface and which is configured to move particles away from the surface.